I've been collecting bookmarks for ages:
http://public.murl.com/moose53/HEALTH_AND_MEDICAL

The 'Health and Medical' folder has many-many sub-folders.

Barb

PS1: If you create an http://www.murl.com bookmark file like I did, it's available to everyone.
PS2: If you want me to extract my links into an HTML file on the internet so that you can incorporate them into your own set of links, just send me an IM; otherwise, you're welcome to use them as they are.